The invention of this application relates to release pins and, more particularly, to quick release pins.
Releasable securing devices, such as ball pins, are commonly used for joining two parts such as the parts of industrial fixtures together. Such ball pins have a hollow, hardened stem insertable through mating bores in the two parts to be joined. The device further includes an abutment surface on one side of the stem configured to be pressed against the one side of the stacked parts. The other side of the device includes depressible or retractable balls near the tip of the pin which are configured to engage the other side of the parts when they are in the extended position.
Quick connect ball locking devices generally include a plurality of detents, such as balls, trapped within a tube but protruding out openings therein. A ball actuator is reciprocal within the tube and movable from a first position wherein the balls are retracted substantially within the tube or moved outwardly a sufficient distance to lock the balls within a mating receptacle. An example of such a ball locking device is shown in U.S. Pat. No. 5,394,594 which is incorporated by reference herein. U.S. Pat. No. 3,277,767 also shows such a releasable securing device and is also incorporated by reference herein for showing the same.
However, in order to provide a complete line of such releasable devices, many sizes need to be produced and it has been found that prior devices, such as are shown in U.S. Pat. Nos. 5,394,594 and 3,277,767, require the stocking of many costly components that are not adjustable or configured to work in more than one size device.
More particularly, and with reference to FIG. 1, a prior art release pin RP is shown having a handle H, a knob K and a shank SH. As can be appreciated, these components can change in size based on the application of the pin. Pin RP further includes a spindle SP that is configured to actuate balls B1 and B2. Pin RP further includes a compression spring CS that is mounted within an enlarged bore EB between knob K and shank SH to urge knob K and spindle SP in axial direction A1. A knob shoulder KS on the knob engages abutment AB on handle H to limit this movement. In the position shown, pin RP is in the locked condition wherein land L of spindle SP holds balls B1 and B2 in a projected position. Knob K, extending from the shank, may be moved manually in axial direction A2 to bring a groove G into registry with the balls and thereby permit radially inward movement of the balls to along ramp R to a release or unlocked condition. Spindle SP of pin RP further includes a spindle shaft SS that extends through a shank bore SB in Shank SH to interengage with knob K. Accordingly, the prior art device's spindle extends from its working end by land L to knob K. Thus, each different length of pin RP requires a corresponding spindle SP. Further, since the spindle is subjected to large loads, the entire spindle, including the spindle shaft, must be made from a high grade and heat treatable material.
Release pins are commonly used as shear pins and typically pass through aligned apertures in adjacent plates. A stop surface at one end of the shank engages one of the plates and the balls when projected lie closely adjacent the remote surface of the other plate. Since it is desirable in many cases to restrict to a minimum axial movement of the pin with respect to the plates, existing release pin assemblies must be manufactured in a large number of effective lengths for each nominal diameter for the pin shank. Thus, pin assemblies must be available in a number of lengths measured from the stop surface on the pin shank to the position of the locking balls.
This multiple length requirement necessitates the manufacture of pin shanks of various lengths, and up to the time of the present invention required a corresponding number of spindles of different lengths. In this respect, one of the problems with existing release pins is that they do not have a shaft design which allows for interchangeable shafts with different lengths and materials. Since the spindle is a portion of the shaft, a different spindle shaft must be used for every length of pin. Further, the material needed for the spindle, to resist the inward load produced by the balls under load, is also used on the shaft even though the shaft has much different material requirements. Thus, there is a need for providing a capability for economically producing different shaft lengths and spindles of various material types as well as various methods of securing the shaft to the release pin assembly.